1. Technical Field
This invention generally relates to devices for directing water in the inlet channels of jet pump drives and in particular it relates to a water directing device known as a top loader having a centralized vertical supporting partition which shields the impeller drive shaft from incoming water pressure.
2. Background Art
Jet pump drives are routinely used as a propulsion means water craft. With the advent of personal water craft, for example the JET SKI by KAWASAKI, there has been an increased interest in maximizing the performance of the jet pump drives.
RHODA, U.S. Pat. No. 3,757,728, discloses what is commonly known as a top loader. A top loader divides the incoming flow of water into two or more portions and directs part of the water to the upper portion of the impeller. This increases the efficiency of the impeller and reduces cavitation. Likewise, STANGELAND, U.S. Pat. No. 4,373,919, teaches an adjustable angle top loading plate.
These and similar devices possess several disadvantages. The first major problem is that the top loading plates are supported along their edges by a pair of side support plate members. When the water craft enters a turn, the side members are presented sideways with respect to the flow of incoming water. This sideways presentation greatly reduces the volume of water directed into the jet drive inlet and significantly decreases impeller efficiency. The second problem inherent in these devices is that they generally require that a portion of the top loader project outwardly from the bottom hull of the water craft which increases the drag significantly. As applied to personal water craft, the protruding portion is a potential safety hazard.
A third problem is that the force of the incoming water in the water intake inlet is applied directly to the impeller drive shaft which extends through the water inlet. The force of the incoming water can actually cause the drive shaft to move and impact the attached impeller with the impeller housing.
What is needed is top loader which increases the water intake during a turn and a means for shielding the drive shaft from the forces of incoming water.
It is therefore an object of the present invention to provide a top loading assembly which increases the efficiency of the jet drive while turning and protects the impeller drive shaft from the forces of incoming water.